Portable printing devices are known in the art. Japanese Patent Application Publication No. 2015-160427 discloses a printing device provided with a belt clip. By attaching the printing device to a user's waist belt with the belt clip, the user can use the printing device portably. To this printing device, a structure disclosed in Japanese Patent application Publication No. 2015-208920 may be applicable. The printing device described in Japanese Patent application Publication No. 2015-208920 includes a rear cover supported to be opened and closed. The rear cover includes support sleeves (corresponding to bearings) for rotatably supporting both ends of a rotational shaft of a platen roller. The support sleeves may be presumably fitted with a holder, and the holder may be presumably fixed to the rear cover with a screw.